AMOUNT OF BIOMAGNIFICATION IN FOOD CROPS.pdf

This is a biology investigatory project on amount of biomagnification in food crops. This document explores the accumulation of heavy metals in various food crops due to industrial pollution, pesticide use, and contaminated water sources. It discusses how these toxic elements enter the soil and are absorbed by plants, ultimately posing health risks to humans through the food chain. It highlights the process of biomagnification, emphasizes the need for monitoring the food crops to minimize issues

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VELS VIDYASHRAM
SENIOR SECONDARY SCHOOL – 600 130

BIOLOGY INVESTIGATORY PROJECT
2024-25
AMOUNT OF BIOMAGNIFICATION IN FOOD
CROPS




A. Nurul Rizwana
XI - A

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INDEX






















E. Meena

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INDEX












SI No. Topic Pg No.
1. Introduction 5
2. What is Biomagnification 6
3. Causes of Biomagnification 7
4. Effects of Biomagnification 8
5. How is Biomagnification is Measured 9
6. Factors That the Amount of Biomagnification Depends On 10
7. Food Crop That Has the Highest Biomagnification 11
8. Chemicals Which Are Responsible for Biomagnification 12
9. Ways to Reduce Biomagnification 16
10. Conclusion 17
11. Bibiliography 18

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Introduction:
➢ Every living organism on this planet requires chemicals to function correctly. However, the
Biomagnification definition suggests that when the accretion of some non-essential chemicals
increases within living organisms, it can become harmful to them.
➢ Biomagnification refers to the process by which harmful substances, such as heavy metals and
persistent organic pollutants, accumulate and increase in concentration as they move through
the food chain.
➢ This phenomenon poses a significant concern for both the environment and human health, as
these toxic substances can persist in ecosystems and eventually affect the food we consume.
➢ Food crops, being a fundamental component of human diets, are particularly susceptible to
contamination through various environmental pathways, including polluted soil, water, and
air.
➢ When these crops are consumed, the contaminants may enter the food chain, potentially
leading to health risks for humans and animals.
➢ Understanding the extent of biomagnification in food crops is crucial for assessing its impact
and addressing the broader challenges associated with environmental pollution.
➢ This study explores the presence of biomagnification in food crops, aiming to identify
common contaminants, their sources, and their potential health implications.
➢ By raising awareness of this issue, the research seeks to highlight the importance of
sustainable agricultural practices and effective pollution control measures to ensure the safety
of food supplies and protect ecosystems.

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What is Biomagnification:-
➢ Biomagnification can be defined as the rise or increase in the contaminated substances
caused by the intoxicating environment. The contaminants might be heavy metals such as
mercury, arsenic, and pesticides such as PCB and DDT.
➢ These substances are taken up by the organisms through the food they consume. When the
organisms in the higher food chain feed on the organisms in the lower food chain containing
these toxins, these toxins get accumulated in the higher organisms.
➢ This occurs when agricultural waste, domestic waste, and industrial waste are dumped in
the natural environment, including water sources such as rivers, lakes, oceans, sewers, and
streams.
➢ The bottom feeders in the food chain, such as zooplankton and algae, consume the toxic
substances in the ocean. These substances are gradually carried to the top of the food chain
(trophic level organisms).
➢ The accumulation of these contaminants increases from level to level.
➢ As humans are high up on the food chain, the accumulation of these contaminants is high.

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Causes of Biomagnification: -
1. Products Used in Agriculture:
➢ Chemical used in the agriculture sector is highly toxic and plays a pivotal part in
biomagnification.
➢ Examples of such chemicals are various pesticides, herbicides, fungicides, and
different inorganic fertilizers.
➢ Ultimately these chemicals penetrate the soil and then are carried to rivers and
oceans via surface runoff.
➢ As a result, they enhance the biomagnification definition of causing harm to an entire
food chain.
2. Industrial Activities:
➢ Toxic by-products released by various industries are a significant cause of
biomagnification.
➢ Additionally, the gas emission by them pollutes the air and harms the ecosystem
even further.
3. Organic Contaminants:
➢ Organic substances like manures and biosolids contain essential nutrients such as
carbon, nitrogen, and phosphorus. Plants primarily use these.
➢ However, the industrial use of these substances causes biomagnification.
4. Mining:
➢ Mining produces by-products like copper, cobalt, zinc, lead and several other toxic
chemicals.
➢ These substances are then deposited in soil and water resources and subsequently
contaminate them.

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Effects of Biomagnification: -
1. Impact on human health:
➢ Biomagnification can cause numerous health complications and diseases in human beings,
such as cancer, heart disease, brain damage, congenital disabilities, respiratory ailments
and so on.
2. Effects on reproductive systems of marine and coastal organisms:
➢ The toxic materials accumulated in the organs of coastal and marine animals affect their
reproduction.
➢ For example, the eggs produced by seabirds with toxins in their system are weak and break
easily, unable to survive even the incubation period.
3. Destruction of coral reefs:
➢ Coral reefs form the base of some of the richest marine ecosystems, supporting many
aquatic species.
➢ However, in the process of gold mining, cyanide is used for leaching.
➢ It is one of the reasons for the destruction of coral reefs. The life cycle of aquatic life gets
affected.
4. Disruption of the food chain:
➢ The release of toxic chemicals into water bodies affects small organisms, which is the
primary cause of disturbance of the food chain.
➢ Smaller organisms are contaminated by toxic substances. On consumption of these fishes,
higher trophic level organisms also get affected.

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How Biomagnification is Measured: -
➢ The amount of biomagnification can be measured by the Biomagnification Factor (BMF),
which is the ratio of the chemical concentration in an organism to the chemical
concentration in its diet.
➢ The BMF is calculated by dividing the chemical concentration in the organism (??????
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chemical concentration in its diet (??????
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BMF =
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➢ A BMF > 1 indicates biomagnification (the metal is accumulating in higher concentrations
in the consumer compared to the food).
➢ A BMF < 1 suggests no biomagnification or even bio dilution (lower concentration in the
consumer).


















Crop Contaminants BMF
Spinach Lead (Pb) 0.1-0.3
Wheat Mercury (Hg) 0.02-0.1
Potato Cadmium (Cd) 0.3-0.7
Lettuce Zinc (Zn) 0.5-1.2
Tomato DDT 0.05-0.2
Carrot PCB 0.02-0.1
Corn HCB 0.01-0.05

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Factors That the Amount of Biomagnification Depends On:-
The amount of biomagnification in food crops depends on several factors, which can be
categorized into three main groups: environmental, plant-related, and contaminant-related
factors.
Environmental Factors:
1. Soil type and quality:
Soil composition, pH, and organic matter content can affect the availability and uptake of
contaminants by plants.
2. Climate and weather:
Temperature, precipitation, and humidity can influence the growth and development of
plants, as well as the degradation and mobility of contaminants.
3. Irrigation water quality:
Contaminated irrigation water can increase the uptake of contaminants by plants.
4. Atmospheric deposition:
Airborne contaminants can settle on plant surfaces or be absorbed through stomata.

Plant-Related Factors:
1. Plant species and variety:
Different plant species and varieties have varying levels of uptake and accumulation of
contaminants.
2. Plant growth stage:
The growth stage of the plant can affect the uptake and accumulation of contaminants.
3. Root depth and architecture:
Plants with deeper or more extensive root systems may be more likely to encounter and
absorb contaminants.
4. Leaf surface area and morphology:
The surface area and morphology of leaves can influence the absorption of contaminants.

Contaminant-Related Factors:
1. Contaminant type and properties:
Different contaminants have varying levels of bioavailability, mobility, and toxicity.
2. Contaminant concentration:
The concentration of contaminants in the soil, water, or air can affect the amount of
biomagnification.
3. Contaminant interactions:
Interactions between contaminants and other substances in the environment can influence
their bioavailability and toxicity.
4. Degradation and persistence:
The rate of degradation and persistence of contaminants can affect their availability for
uptake by plants.

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Food Crop That Has the Highest Biomagnification: -
➢ According to the study made by biologists, rice has higher concentrations and
biomagnification of metals and metalloids than sugarcane.
➢ Rice paddies have stronger biomagnification patterns than sugarcane ecosystems for metals
like chromium, cadmium, copper, mercury, lead, and zinc.
➢ The strongest biomagnification was for zinc and mercury while cadmium, chromium,
copper, and lead have an intermediate level of biomagnification.










Contaminants BMF
Lead (Pb) 0.02-0.1
Arsenic 0.5-1.0
Mercury (Hg) 0.01-0.05
Cadmium (Cd) 0.1-0.4
Zinc (Zn) 0.3-0.8
DDT 0.01-0.05
PCB 0.005-0.02
HCB 0.01-0.03

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Chemicals Which Are Responsible for Biomagnification: -
1. Dichloro Diphenyl Trichloroethane (DDT):
➢ It is a toxic, man-made, persistent organic pollutant (POP) that was once widely used as an
insecticide.
➢ Studies have proved that DDT has serious implications on human and animal health.
➢ Low-to-moderate exposure (10mg/kg) may result in nausea, diarrhoea and irritation of
eyes, nose or throat, while higher doses (16mg/kg) can lead to tremors and convulsions.
➢ It can even cause chromosomal damages in some cases.
➢ Moreover, because of its non-biodegradable character, it can remain in soil or water for
many years leading to a very dangerous and concerning process – biomagnification.
➢ It accumulates in the fat and tissue of organisms.
➢ Because it can't be metabolized or excreted, it's passed on to the next higher trophic
level. This results in higher concentrations of DDT in predators than in prey

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2. Polychlorinated biphenyl (PCB):
➢ It is a group of man-made chemicals that bioaccumulate and bio magnify in living
organisms.
➢ PCBs are toxic and have negative effects on biological organisms.
➢ They were produced from the 1920s to 1979, but can still be found in the environment
today.
➢ PCBs are lipophilic, meaning they bind to adipose tissues in organisms.
➢ It can cause health issues like nervous system disorders, such as impaired cognitive and
psychomotor function, attention, learning, and memory deficits, immune system
dysfunctions, such as thymic atrophy and suppressed immune responses and
cardiovascular diseases, such as stroke and hypertension.
➢ Since PCBs are found in the organic part of the soil and marine and lake sediments, they
can be absorbed by plants and ingested by aquatic organisms.
➢ Due to their poor degradability, this phenomenon leads to biomagnification along the
trophic levels of the food chain.

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3. Hexachlorobenzene (HCB):
➢ Hexachlorobenzene (HCB) is a persistent organochlorine chemical that was once used as a
pesticide but is now banned globally.
➢ Hexachlorobenzene is a very persistent environmental chemical due to its chemical stability
and resistance to biodegradation.
➢ Hexachlorobenzene is very slow to breakdown in air and is subject to long-range transport
in the atmosphere.
➢ Hexachlorobenzene sticks strongly to soil and can be slowly degraded by microorganisms.
Half the hexachlorobenzene in soil will disappear in 3–6 years.
➢ Hexachlorobenzene is highly bioaccumulated by animals that live in hexachlorobenzene-
contaminated water.
➢ Brief exposure to very high levels of hexachlorobenzene may cause adverse effects on the
nervous system such as weakness, tremors, and convulsions; skin sores; and liver and
thyroid effects.
➢ Long-term exposure can cause damage to the liver and reproductive system and can cause
developmental effects.

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4. Heavy Metals:
➢ The increase in industrialization and urbanization has accelerated the emission and
pollution of metal from anthropogenic operations. Mining, smelting and metal treatment,
oil and gas, wastewater, road traffic, and waste dumping sites have contributed to metal
pollution, deteriorating the environment and human health
➢ The toxic heavy metals like mercury, arsenic, lead and cadmium increases progressively
within a food chain, accumulating in higher concentrations in organisms at each trophic
level, the higher up the food chain you go, the greater the concentration of the heavy metal
becomes.
➢ Heavy metal pollution is a serious problem that can have wide-ranging and long-lasting
impacts on human health and the environment.
➢ People are exposed to heavy metals in a few different ways, primarily through drinking
water or food (crops can uptake metals from contaminated soil or meat and fish products
may contain bioaccumulated metals).
➢ Many heavy metals are poisonous to humans, even in small concentrations.

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Ways To Reduce Biomagnification:-
Reduce use of toxic chemicals:
➢ One effective solution to address the problem of biomagnification is to reduce the use of
toxic chemicals in the environment.
➢ This can be achieved through a variety of methods, such as implementing stricter
regulations on the use of pesticides and herbicides in agriculture, reducing the use of toxic
industrial chemicals in manufacturing, and promoting the use of alternative, non-toxic
chemicals in everyday products.
Incorporate sustainable agricultural practices:
➢ Another approach to address biomagnification is to promote sustainable agricultural
practices that minimise the use of chemical inputs.
➢ For example, organic farming practices can reduce the number of chemical fertilisers and
pesticides used in agriculture, thereby reducing the amount of toxins that enter the food
chain.
Promote use of non-toxic cleaners:
➢ Efforts can be made to promote the use of non-toxic, biodegradable cleaning agents and
detergents.
➢ These products can be used to clean up contaminated sites and prevent the release of toxins
into the environment.
Incorporate Bioremediation techniques:
➢ Bioremediation involves the use of naturally occurring microorganisms to break down
toxic substances into less harmful compounds.
➢ This approach can be used to clean up contaminated soil, water, and air, and can help to
reduce the accumulation of toxic substances in the food chain.
➢ Industrial effluents are wastewater or liquid waste generated from industrial processes.
➢ These effluents can contain various pollutants such as heavy metals, organic compounds,
and nutrients that can be harmful to the environment and human health.
➢ Bioremediation is an effective method for treating industrial effluents as it uses natural
biological processes to break down and remove pollutants.
Raise Awareness:
➢ Raise awareness to farmers about the causes and effects of biomagnification.
➢ Highlight how pesticide residues can accumulate in the environment and affect not only
their crops but also the health of their families, livestock, and wildlife.
➢ Encourage farmers to adopt integrated pest management (IPM) techniques that rely on
biological controls, crop rotation, and cultural practices to minimize pesticide use.
➢ Introduce them to the benefits of organic farming and biofertilizers.
➢ Advocate for regular soil testing to assess contaminant levels and identify areas where
pesticide use needs to be reduced

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Conclusion:-
Biomagnification, the progressive accumulation of toxic substances such as heavy metals and
persistent organic pollutants in living organisms, has become a significant concern, particularly
for agricultural ecosystems. Contaminants like lead, mercury, and pesticides infiltrate soil, water,
and air through agricultural runoff, industrial effluents, and other environmental pathways,
ultimately finding their way into food crops and the broader food chain.
The findings reveal that certain crops, such as rice, exhibit a higher tendency for biomagnification
due to environmental and biological factors, including soil type, irrigation practices, and
contaminant characteristics.
Heavy metals like mercury and lead were identified as particularly detrimental, posing risks such
as neurological disorders, cardiovascular diseases, and reproductive health issues in both humans
and wildlife. Similarly, persistent organic pollutants like DDT and PCBs demonstrate a long-term
impact due to their resistance to degradation and propensity for bioaccumulation.
To mitigate these effects, adopting sustainable agricultural practices, reducing the use of toxic
chemicals, and implementing bioremediation strategies are crucial. Raising awareness among
farmers about integrated pest management techniques and encouraging organic farming can
further reduce the risk of contamination.
This research underscores the urgent need for stringent pollution control measures and
sustainable practices to safeguard the food supply and ecosystems. By addressing the sources of
contamination and promoting cleaner agricultural and industrial practices, we can ensure a
healthier environment and mitigate the long-term impacts of biomagnification on human and
ecological health.

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Bibliography: -
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